CVTs are known. CVTs include a driven clutch operatively coupled to a drive clutch through a belt. The drive clutch is coupled to an input shaft of the CVT and the drive clutch is coupled to an output shaft of the CVT. As is known in the art, as the rotation speed of the input shaft varies, the drive clutch, the driven clutch, and the belt cooperate to vary the rotation speed of the output shaft. Typically, the drive clutch, the driven clutch, and the belt are positioned within a housing and ambient air is moved through the housing to assist in cooling the drive clutch, the driven clutch, and the belt.
It is commonplace for the CVT to have input from a power source such as an internal combustion engine and output to a geared transmission. Examples of CVT applications in vehicles may be seen in any of the following disclosures, namely: U.S. Pat. Nos. 8,827,028; 8,827,019; and US Publication 20150061275, the subject matter of which is incorporated herein by reference. An example of a CVT is shown in US Publication 20160061314, the subject matter of which is incorporated herein by reference. A vehicle for use with the present CVT is more fully described in our application (Ser. No. 62/438,267) filed on Dec. 22, 2016.
The present disclosure relates to CVTs. By way of example, the present disclosure relates to systems and methods to allow the CVT to brake the vehicle, and/or start the engine through the CVT by driving the wheels of the vehicle.
In an exemplary embodiment of the invention, a CVT includes a drive clutch having inner and outer sheaves rotatably coupled to a drive clutch shaft and a driven clutch having inner and outer sheaves rotatably coupled to a driven clutch shaft. The CVT further includes a one-way clutch; a flanged sleeve operatively coupled to the drive clutch shaft and generally positioned intermediate the inner and outer sheaves of the drive clutch, with the on-way clutch positioned over the sleeve. The flanged sleeve is rotatably fixed relative to the drive clutch shaft when operating in a first direction and being moveable axially relative to the drive clutch shaft and towards the outer sheave when operating in a second direction.
In another embodiment of the invention, a CVT comprises a drive clutch having inner and outer sheaves rotatably coupled to a drive clutch shaft and a driven clutch having inner and outer sheaves rotatably coupled to a driven clutch shaft. The CVT further comprises a thrust member positioned over the drive clutch shaft and adjacent the inner sheave of the drive clutch; and a flanged sleeve operatively coupled to the drive clutch shaft and generally positioned intermediate the inner and outer sheaves of the drive clutch, with a portion of the flanged sleeve being adjacent the thrust member. The flanged sleeve is rotatably fixed relative to the drive clutch shaft when operating in a first direction and being cooperable with the thrust member to move the flanged member axially relative to the drive clutch shaft and towards the outer sheave when operating in a second direction.
In another embodiment, a continuously variable clutch (CVT) comprises a drive clutch having inner and outer sheaves rotatably coupled to a drive clutch shaft; and a driven clutch has inner and outer sheaves rotatably coupled to a driven clutch shaft. One of the sheaves has a helix fixed to the sheave; the helix having helical surfaces, and the other of the sheaves having engagement members cooperating with the helical surfaces to effect movement of the two sheaves relative to each other. The one sheave is comprised of a first material having a density lower than 4 gr/cc and the helix is comprised of a second material having a density greater than 4 gr/cc.
The above mentioned and other features of the invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings. These above mentioned and other features of the invention may be used in any combination or permutation. The invention is particularly intended for use with Powersports vehicles, such as ATVs, snowmobiles, utility vehicles and the like, but is useable with almost any vehicle.